[Coco] ?PEEK(&HFF90) RETURNS 126 ON MY UNUPGRADED 26-3124?
coco at yourdvd.net
coco at yourdvd.net
Wed Apr 25 15:51:46 EDT 2007
Honestly - it could have been my sister's kids that violated the
package, rather than the post office - it was WELL packaged. :-)
(Perhaps I am cursed - maybe someone I outbid HEXed me :-) )
p.s. - I am through bidding for awhile (as long as I can resist the urge
to SEARCH eBay - it's more difficult than quitting smoking, not bidding
that is) -r
> -------- Original Message --------
> Subject: Re: [Coco] ?PEEK(&HFF90) RETURNS 126 ON MY UNUPGRADED 26-3124?
> From: Mark Marlette <mark at cloud9tech.com>
> Date: Wed, April 25, 2007 12:42 pm
> To: coco at maltedmedia.com
> Man yo are hitting the first for everything. I'll maqke sure in the
> future that the IC is in more protected place. The Antistat foam and
> bubble packaging usually is enough.
> The MPI is simple. The equations are simple. The interface and design
> are VERY problematic.
> Quoting coco at yourdvd.net:
> > got the gal replacement for the pal. it was squished by the post office
> > - looked like they stepped on the sucker, but i straightened all those
> > pins out plugged 'er in and voila - coco 3 mpi :-)
> > While I had the 3024 MPI opened, I noticed just how different it is
> > the 3124. The 3024 should be easy to build an exact clone but using
> > gal instaed of the tandy pal - all other circuits at first glance
> > to be standard ttl and some power supply stuff. i made one some time
> > using 74ls138's and 74ls374 latches, etc. to clone the mpi - a lot of
> > discrete circuitry. had 8 slots, but otherwise worked like a coco 3
> > mpi. I had planned to replace the 138's with 154's and make 16 slots
> > (major overkill), but then i popped by paul bartons site and he
> > mentions the upper bit of both nybbles being used as an enable disable
> > of the associated signal. I didn't think the multi-pak worked like that
> > and didn't account for it in the thing i built, but it still worked :-)
> > one day i'll dig all this junk i made out of storage and stick the
> > schematics somewhere.... r
> > p.s. i made the slots out of a short piece of ribbon cable and a 40
> > ids connector.
> >> -------- Original Message --------
> >> Subject: Re: [Coco] ?PEEK(&HFF90) RETURNS 126 ON MY UNUPGRADED
> >> From: Mark Marlette <mark at cloud9tech.com>
> >> Date: Tue, April 24, 2007 10:57 am
> >> To: Robert Gault <robert.gault at worldnet.att.net>
> >> Cc: coco at maltedmedia.com
> >> Robert,
> >> I don't have the data right in front of me....hold on let me check
> >> C-9's CVS for the mpak manual...
> >> Nope...have to add it...
> >> I looked at my source to the .abl code for the GAL, 26-3024 update.
> >> The new range of the MPI is $FF40-$FF7F.
> >> If I looked at the 3124 mod that I have already documented at home I
> >> could quickly figure out what it's original range was. From my web
> >> page it appears that the MPIs unmodified range went into the GIME's
> >> address space($ff90).
> >> The peek makes sure that it is not. This si the first I have heard
> >> that it isn't working.
> >> Done this MANY years ago so I don't recall.
> >> Sorry for the slow response. Was gone over the weekend and have many
> >> business/list emails to reply to.
> >> Regards,
> >> Mark
> >> Mark Marlette wrote:
> >> Robert,
> >> What GIME is in your CoCo?
> >> Test performed on the same CoCo?
> >> I'm sure I have done this test on both MPIs. Been too long ago.
> >> Thanks,
> >> Mark
> >> At 4/21/2007 02:12 PM, you wrote:
> >> Marks test of ?peek(&hff90) returns 255 on all of my 3024 multi-paks,
> >> however it returned 126 on my 3124. I opened the 3124 and there is no
> >> satellite board nor any piggy backed chips nor any mod of any kind - i
> >> can't see that this pak has been upgraded. Does this test only work
> >> the 3024's? thanks - Rob
> >> I just tried a test with a Coco3 and an MPI 3024. Without the MPI the
> >> PEEK returned 126 and the same with the MPI.
> >> What are you trying to determine with this PEEK, whether the MPI was
> >> upgraded for Coco3 use?
> >> --
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> >> Coco at maltedmedia.com
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> > --
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